Flexible waterproof leather and method of making it.



No Drawing. Application filed October 7,1910, Serial No. 585,795.

' gsTaTs ANT onnron JOHN WESLEY BARBER, or NEWTON, MASSACHUSETTS.

FLEXIBLE WATERPROOF LEATHER AND METHOD OF MAKING IT.

To all whom it may concern: i

Be it known that I, JOHN WESLEY BAR- BER, a citizen of the UnitedStates, of Newton, in the countyof Middlesex-and State shall retain itstexture and natural wearof Massachusetts, have invented certain new anduseful Improvements in Flexible Waterproof Leather and Methods of MakingIt, of which the following is a specification.

Many attempts have been made to furnish leather which is water-proof,and to furnish leather which is flexible or pliable, but all, so far asI am aware have either failed entirely, or have resulted in seriouslyaffecting the quality or life of the leather, or in rendering itnecessary to change from the usual processes in making up the leatherinto such articles as boots, and shoes, harness, etc. Those treatmentswhich have seeme to attain the best results, have failed in respect tothe duration of the efl'ect; in other words, the effects of thetreatments would be lost after some days, especially in the case of thesoles-of boots and shoes worn in melting snow.

After experiments and tests for'some five years,'I have succeeded inattaining the ob ject of my present invention, which is to produceleather for various purposes,'wh1ch leather shall be pliable andwater-proof during practically its entire life of use and wear, mayretain the usual odor of leather,

ing qualities, and which will require no .special changes from the usualprocesses and steps of convertingit into finished articles such as bootsand shoes, straps, harness, saddlery, etc. In the following descriptionof one way of carrying out my invention, the term leather will beemployed in its broad significance.

The leather is immersed successively in a and preferably with anintervening and a following heating treatment. In each bath I employpetrolatum, with some paraffin, the proportions of the substances in onebath varying from the proportions in the other bath. The petrolatum isemployed especially for the purpose of imparting pliability orflexibility to the leather. It possesses some water-proofing qualities,but the paraflin is relied upon mainly to impart water-proofingqualities.

Bath No. 1, preferably consists of approx- Specification of LettersPatent.

imately 7 5 parts of petrolatum to 25 parts of'paraflin, while bath No.2 preferably consists of approximately 45 parts of petrolatuin to partsof parafiin, but I do not limit myself to these proportions. Each bathis heated to keep it in a condition of suficient fluidity so that itwill penetrate the pores of therleather immersed therein. The Itemperature at which each bath will be kept, will depend somewhat uponthe nature and thickness of the leather. The leather is first immersedin bath No. 1 for a sufficient length of time at a comparatively lowheat, and is then, after removal from the bath subjected to a heat,preferably in an. open oven of some nature, the temperature beingsufficiently low, not to destroy the life of the leather, thissubjection of the leather to'an open heat permitting the leather tofully absorb the substances remaining in or on the leather. Then theleather is immersed in the second bath which contains. a greater per--centage of paraflin wax that, will completely water-proof the leather. Apreferable final treatment is to again subject the leather to an openheat treatment.

Neither the petrolatum nor the para'fiin ments. On a large scale,however, machinery can be employed for the immersions, and to carry theleather through ovens or heating apparatus having means for venti-'lating the same by blast or suction devices. plurality of baths, two inthe present case,

leather, for mens heavy boots, the length of time of immersion at theheat mentioned may be increased. Experience has shown that a temperatureof 160 F. is the extreme limit of safety in order not to injure theleather by over-heating. And at such temperature, it is best to givevery short immersions, say, one or two seconds. The lowest limit of heatat which the mixture will remain in condition to serve forimpregnations, I have found by experience to be ap- 160 short immersionsof 1 or 2 seconds.

150 immersions from 3 to 5 seconds. 1400 it C 6 H C 1300 I C C $4 1200(C C C it 1100 C 6 C (G The reason why there may be such a greatlatitude at the lower temperatures as 110,

120, and 130, is that leather will only absorb a. certain amount, andany extra amount deposited as will be the case when the bath is not veryfluid, will drip off during the next step of the process.

After withdrawal from bath No. 1, the leather is transferred to a heatedreceptacle or oven in which the heat should be kept practically uniform,at not over approxi-. mately 120 F. The temperature for this heat may,however, vary from 110 to 130. During this heating treatment, theleather is preferably given some kindof turning over motion, to avoiddiscoloration of the leather by uneven absorption. After the completeabsorption has taken place during this heating treatment, which mayaverage 10 minutes in a ventilated oven the leather is placed in bathNo. 2, which is preferably heated to a temperature somewhat higher thanbath No. 1. For instance, at first the temperature of bath No. 2 mightbe as high as 160 F., or even somewhat higher. At a temperature of 160F., the leather may be given only a series of brief immersions withintervening time, such as 2 seconds. At lower temperature, it may beleft a longer time in the bath. When the process is being carried out inconnection with large quantities of leather, and requiring largereceptacles for the immersions, an even heat at from 130 to 140 isadvisable, after which the leather is transferred to an open orventilated heated oven or'receptacle where it will remain lon enough forcomplete absorption of the ingredients.

Bath No. 2 is intended to make the waterproofing more perfect. The firstbath chiefly imparts flexibility or pliability to the leather while thesecond bath adds more of a substance which renders the leather durablywater-proof.

2 Owing to the fact that the leather is actually immersed and not simplyallowed to rest with one surface in a bath, both the top and thebottom-surfaces of the sole leather will absorb an equal amount of thewaterproofing material. Then, when the boot or shoe is being worn, anymoisture which might be taken up in any degree, will not be communicatedthrough the sole, even if the middle portion of the leather should notbe thoroughly impregnated. This is because the thorough impregnation ofthe upper surface of the sole leather will prevent transmission ofmoisture to the inside of the shoe.

; This advantage is still true after the shoe has been worn so long thatthe under thoroughly impregnated surface has been worn away. The uppersurface still remains in condition to prevent the transmission ofmoisture to the inside of the shoe, because none of the substancesapplied are volatile.

When the leather being treated is to be used not for boot and shoesoles, but articles where there is little or no surface wear, I havefound that one treatment in the first bath at a low heat, for alongimmersion, followed by the treatment described in an open low-heatedoven or receptacle will give permanent pliability to the leather andprolong its life.

I have found it very essential to employ only the very best quality ofpetrolatum, and that perfect absorption can only be obtained by thisrefined article. Even of this grade, I find that only the short, as itis technically called, can be used successfully. Grades that are at allstringy will not answer. The grade of paraflin wax employed, is thatreferred to as test 128 1 10. These two substances effect a perfectunion with each other, and cause no possible harm to the leather. Theleather absorbs them perfectly, without parting with its ing stitched'bymachinery with a waxed thread. The waxed thread is used while warm. Thewarmth of the waxed thread serves to act upon the substances in theleather so as to seal each stitch and make the sewing water-proof.

The ordinary heating used in burnishing, after the edges of the solehave been inked, seals the coloring matter and by the same operationbrings the water-proofing substances to the edge surfaces of the sole.

As has been stated, the two compositions eflect a perfect union witheach other although they are successively applied to the leather. Thefirst composition contains an excess of petrolatum andimparts-pliability or flexibility to the leather, as has been stated.The nature of petrolatum, however, is such that it is liable to exude orbe worked out from the leather in use. The composition in which theleather is next immersed contains paraffin in considerably greaterproportion than the composition in which the leather was first immersedand said paraflin, owing to its crystalline nature, remains in thesurface portions of the leather,

and confines in the body of the leather all the composition materialpreviously applied, and hence the capability of the leather to retainits moisture-proof quality is insured.

While I have referred particularly to the waterproofing material orcomposition consisting of petrolatum and paraffin, I do not limit myselfstrictly thereto, as other equivalent waterproofing materials orcompositions capable of attaining the objects stated, may be substitutedtherefor.

, Owing to the fact that the leather is impregnated with water-proofingmaterial, the stitches and stitch holes are rendered impervious tomoisture, this resulting from the action upon the waterproofing materialof the warmed or heated sewing strands.

'1. The method of rendering leather pliable and waterproof,consisting'in immersing it successively in dissimilarly proportionedcompositions of petrolatum and paraffin, the proportion of petrolatum inone composition being in excess, to impart flexibility to the leather,and the proportion of paraifin in the succeeding composition beingconsiderably in excess of that in the preceding composition, to increasethe durability of the resistance to moisture and to confine thebefore-applied composition.

2. The method of rendering leather pliable and waterproof, consisting inimmersing it successively in dissimilarly proportioned compositions ofpetrolatum and paraffin, the proportion of paraffin in the compositionused for the second immersion being greatly in excess of that in thefirst used composition, to increase the durability of the resistance tomoisture.

3. The method of rendering leather pliable and waterproof, consisting inimpregnating substantially the entire" body of the leather by acomposition consisting of petrolatum and paraffin in substantially theproportions of three parts of the former to one of the latter, and thenimpregnating the surface portions of the leather by a compositionconsisting also of petrolatum and paraflin in substantially or nearlyequal parts.

4. As an article of manufacture, leather impregnated with petrolatum andparaflin, the proportion of the paraffin relatively to the petrolatumbeing greater in the surface portions of the leather than in theintermediate or body portion.

5. The method of rendering leather pliable and waterproof, consisting-inimpregnating it successively with dissimilarly proportioned compositionsof hydrocarbons possessing respectively the qualities of impartingflexibility to the leather and waterproofing it, theproportion of thehydrocarbon which possesses waterproofing qualities being in excess inthe later used composition. over that in the previously appliedcomposition.

6. As an article of manufacture, leather impregnated with successivecompositions, each composition being composed of different hydrocarbonspossessing respectively the qualities of imparting flexibility to theleather and waterproofing it, and the composition used for the laterimpregnation having a larger proportion of the water proofingcomposition than the previously applied composition.

In testimony whereof l have aifixed my signature, in presence of twowitnesses.

JOHN WESLEY BARBER. Witnesses:

. A. W. HARRISON,

P. W. Pnzzn'r'ri.

